Do you bounce when you run?

18 June 2018

From this closer look at running form, the focus is on learning how bounce in your running stride can reduce your performance and increase your risk for injury. If you would like to look back on my previous run form articles, select the links below.

Before we look closer at run bounce, I like to re-state my stance on running form, which is…

Good form means you are using the correct muscles at the correct time to decrease the impact on your body. You are going to have your own running style. The goal is not to entirely change your style, but to look for the weak running form metrics and find ways to make small incremental changes. These small changes in your running routine over an extended period of time will have you running more efficiently and injury-free.

What is Run Bounce and Why Does it Matter?

When we look at running form with this insight, we are better able to understand why run bounce in your stride is important. The bounce, or vertical oscillation of your pelvis, refers to the up and down movement of your body while running. The larger your bounce, the more energy is taken away from propelling you forward. Just how much energy is lost?

Consider a 4:00:00 marathon runner with an average run cadence of 165 strides per minute. This runner will take 39,600 steps over the course of 26.2 miles. If each of these strides contains an excess of 1 inch of vertical oscillation, the runner has to spend an unnecessary amount of effort bouncing over a mile vertically during the race!

From this example, it should be clear that reducing run bounce in our stride is beneficial for the reason of not wasting any energy. So how exactly do we determine our own vertical oscillation?

Measuring Vertical Oscillation

There was a time when we could only measure vertical oscillation in the lab or give a rough estimate using the visual eye test. Thankfully, technology has evolved that allows for many mobile devices to give us a run bounce value. Many Garmin devices, for example, measure run cadence, stride length, ground contact, and vertical oscillation. The watch and heart rate monitor measure “bounce” by tracking the number of centimeters your torso moves from a fixed point during each stride. Garmin then provides the user with a vertical oscillation ratio which is vertical oscillation divided by stride length – since these two movement are correlated in our running. Stride length is our movement horizontally, while bounce is our movement vertically.

The vertical oscillation ratio from a Garmin device provides the runner with an easy to understand percentage. The lower the vertical oscillation percentage, the less bounce in our stride and and less wasted energy during our run.

How do I reduce bounce?

As mentioned, run bounce is intertwined with stride length. Once we know key metrics such as cadence, vertical oscillation, and ground contact time, we should look to improve our cadence first. If we can run with a higher more efficient cadence, decreases in vertical oscillation should also occur.

Bounce is also influenced by our body position while we are running. A more upright (standing) running style is typically going to result in more vertical oscillation. Whereas, a running style the leans from the ankles (and maintains a straight line through the knee, hip, back, shoulders, and head) is going to propel your body forward more significantly and reduce the bounce in your stride.

Here are some visualizations to help you to start decreasing your run bounce and improving your overall running form…

(1) The Egg – Imagine you have an egg on your head and you are trying to keep it from falling. This will engage your core and minimize excess up and down movements in your stride.